The use of compounds having an oxime ester structure as photoinitiators has been well known in the art, and for example, patent documents having Publication Nos. CN1241562A, CN101508744A, CN101565472A, CN103293855A, etc., have disclosed different carbazole oxime ester photoinitiators and ketoxime ester photoinitiators. These disclosed photoinitiators can satisfy normal application requirements in the current field of photocuring such as display panels, color filters, etc., to different extents.
However, since the development of electronic technologies changes rapidly, the existing products started to exhibit deficiencies in some application fields, and the requirements for photoinitiators are higher due to replacement and upgrade of products. At present, for example, most of photoresists used for space control materials do not have good heat resistance, collapse is prone to occur in the process of baking or packaging to result in the shrinkage of space materials, whereas intended increase of the height of the space control material in the process of coating, development by exposure, or the like will result in increased cost, and small molecules melted out upon collapse due to heating will cause contamination of liquid crystal. Furthermore, for example, in the production of premium color filters, the photoinitiator has to meet basic requirements of having high solubility and good thermal stability on the one hand, and its high color quality performance requires a highly colored resist on the other hand. However, as the content of pigments increases, the curing of color resist becomes more difficult, and there are also relatively high requirements for the clarity and the integrity of images after curing. This requires an initiator having a higher photosensitivity to solve the problems described above.
In the field of photocuring, a photoinitiator, which has a high photosensitivity and a high stability and is easy to be prepared, is still the first choice in the development of this field, and the research and development of a photoinitiator having higher performances is always a key task in this field.